Neisseria gonorrhoeae (gonococci) is the etiologic agent of gonorrhea, an important sexually transmitted disease found throughout the world. In males, the infection is easily diagnosed and treated. However, less than 25% of females with gonorrhea have a readily discernable endocervical infection. As many as 10 to 15 percent of infected women develop gonococcal pelvic inflammatory disease which can result in damage to the fallopian tubes. Subsequently, gonococci may ascend to the ovaries and into the peritoneal cavity which may lead to sterility and which in some cases can be life threatening. The disease if left untreated in either males or females can also cause gonococcal arthritis.
Traditionally, diagnosis of gonorrhea is accomplished by culturing the organism from a clinical specimen suspected of harboring N. gonorrhoeae. Culture techniques include procedures described in, Criteria And Techniques For The Diagnosis Of Gonorrhea, published by the Center for Disease Control, Atlanta, Ga. These culture techniques are laborious and time consuming requiring a minimum of 24 hours of culturing and result in presumptive identification of N. gonorrhoeae. Confirmation of the identification is typically accomplished by sugar fermentation patterns, fluorescent antibody staining, or agglutination assays.
In order to improve the efficiency and accuracy of the detection of N. gonorrhoeae, alternative methods such as enzyme immunoassay have been developed. (Grubin, L., and Osborne, N. G., Obstet. Gynecol. 69:350-353 (1987)). DNA hybridization assays have also been described for the detection of N. gonorrhoeae. (U.S. Pat. No. 4,900,659 by Lo; Pauke, E. S., et al., J. Clin. Microbiol. 29:883-888 (1991); Torres, M. J., et al. Mol. Cell. Probes 5:49-54 (1991); Totten, P. A., et al., J. Infect. Dis. 148:462-471 (1983); and Perfin, et al., J. Infect. Dis. 152:59 (1986)).
U.S. Pat. No. 5,162,199 to Stem and Wolff addresses the use of DNA probes for the detection of N. gonorrhoeae and N. meningitidis using hybridization assays such as slot blots and southern blots. The probes were derived from the PHI, Pil I, Iga2, Iga1, Opa1, Opa2, and Opa3 genes which code for various Neisseria specific proteins.
In selecting DNA probe sequences for the detection of N. gonorrhoeae, it is important to recognize that N. gonorrhoeae and N. meningitidis exhibit up to about 93% chromosomal DNA hornology (Hoke and Vedros, Int. J. Syst. Bacter. 32:57-66 (1982)). Thus, in order to develop effective materials and methods for the diagnosis of N. gonorrhoeae it is important to select nucleotide sequences that are specific for N. gonorrhoeae and which exhibit no cross reactivity with other Neisseria species or other bacteria. The sequence known as pil E has been described by Meyer, T. F., et al., Proc. Natl. Acad. Sci. U.S.4.81:6110-6114 (1984). The pil E gene codes for a predominant surface antigen of N. gonorrhoeae which allows adhesion of the bacterium to various host cells. Pil E expression in the MS 11 strain of N. gonorrhoeae is controlled by at least two and possibly three genetic loci dispersed over a large region of the N. gonorrhoeae chromosome.
Also of interest to the background of the present invention is a technique useful in amplifying and detecting target DNAs known as the polymerase chain reaction. The polymerase chain reaction provides a method for selectively increasing the concentration of a target DNA having a particular sequence. Details of the polymerase chain reaction are provided by Mullis, K. et al. U.S. Pat. No. 4,683,202; Erlich, H., U.S. Pat. No. 4,582,788; Saiki et al., U.S. Pat. No. 4,683,195; Mullis, K. B., Cold Spring Harbor Symp. Quant. Biol 51:263-273 (1986); Saiki, R. K. et al., Bio/Technology 3:1008-1012 (1985); and Mullis, K. B., et al. Meth. Enzymol. 155:335-350 (1987), all of which are incorporated herein by reference.
Despite the aforementioned methods, there remains a need for a rapid, sensitive, specific and reproducible method for the detection of Neisseria gonorrhoeae.